The exhibition, titled Here's One We Made Earlier, charts the development of broadcasting for young viewers and listeners since the birth of the BBC's first children's programme, Children's Hour, in 1922.

The Clangers, the knitted, whistling alien creatures that engrossed children at the end of the 1960s and start of the '70s, are to make a comeback in a new series next year.

Lovable stuffed cat Bagpuss and his friends Professor Yaffle, Gabriel Croaker and the mice make an appearance. They originally appeared in the mid-1970s and were created, like The Clangers, by Oliver Postgate's Smallfilms.

Here is one they made earlier - this replica of Thunderbirds' Tracy Island, constructed using a washing-up bottle, pipe cleaners and a cereal carton, among other things, was one of Blue Peter's most famous do-it-yourself projects. The full instructions are available here.

Scripts, photographs, records, annuals and a school uniform from Grange Hill tell the story of the fictional London secondary school, which was the setting for on-screen teenage sagas for 30 years from 1978.

Gordon the Gopher gained fame as Phillip Schofield's squeaky sidekick in the Children's BBC Broom Cupboard in the 1980s.

The set for Strange Hill High, one of the corporation's more recent major children's series, is on show. The CBBC programme, which combines rod puppetry with CGI and stop-motion filming techniques, was created by former Simpsons showrunner Josh Weinstein.

Image copyrightNathan Cox

Otis the Aardvark, who has been a favourite on children's BBC programmes for 20 years, was given a final brush-down before the opening of the exhibition, which runs until 12 October.